US 7339490 B2
A modular sensor assembly for sensing conditions at a computer rack, such as environmental conditions. The sensor assembly includes an elongate flexible body, configured to attach to a computer rack, with a plurality of addressable sensors, disposed along the body and interconnected to a common connector wire. A connector wire lead is provided to interconnect the connector wire to a central system configured to receive and interpret data from the plurality of sensors relating to conditions associated with the computer rack.
1. A modular sensor assembly for sensing a condition at a computer rack, comprising:
a) an elongate flexible body, configured to attach to a computer rack;
b) a plurality of addressable sensors, disposed along the body and interconnected to a common connector wire; and
c) a connector wire lead, configured to interconnect the connector wire to a central system configured to receive and interpret data from the plurality of sensors relating to conditions associated with the computer rack.
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11. A sensor system, comprising:
a) a computer rack;
b) a modular sensor assembly, having a flexible elongate body, attached to the computer rack;
c) a plurality of addressable sensors, disposed along the elongate body of the modular sensor assembly, and interconnected in parallel to a common connector wire, configured to independently measure an environmental condition in the immediate vicinity of the sensor;
d) a connector wire lead, interconnected to the common connector wire; and
e) a central system, interconnected to the connector wire lead, configured to receive and interpret data from the plurality of addressable sensors.
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a) a pair of substantially flat flexible conductors, disposed on a substrate, a first of the conductors a ground wire, and a second of the conductors being a data wire; and
b) a ground lead of each sensor device being connected to the first conductor, and a data lead of each sensor device being connected to the second conductor.
26. A system in accordance with
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28. A computer rack system, comprising:
a) a generally upright rack body, configured to support heat-generating electronic devices, and to allow cooling air to flow therethrough;
b) a modular sensor assembly, attached to the rack body, comprising an elongate flexible sensor body having a plurality of addressable sensors connected in parallel to a common connector wire, each sensor being configured to generate a digital signal representative of an environmental condition; and
c) a connector board, associated with the rack body, interconnected to the connector wire and to a central computer system configured to receive data from the plurality of sensors and to monitor environmental conditions associated with the rack.
1. Field of the Invention
The present invention relates generally to a sensor system for monitoring conditions in a data center.
2. Related Art
A data center may be defined as a location, e.g., a room, that houses numerous printed circuit (PC) board electronic systems arranged in a number of racks. A standard rack may be defined as an Electronics Industry Association (EIA) enclosure, 78 in. (2 meters) high, 24 in. (0.61 meter) wide and 30 in. (0.76 meter) deep. Standard racks may be configured to house a number of PC boards, e.g., about forty (40) PC server systems, with some existing configurations of racks being designed to accommodate up to 280 blade systems. The PC boards typically include a number of components, e.g. processors, micro-controllers, high speed video cards, memories, and the like, that dissipate relatively significant amounts of heat during the operating of the respective components. For example, a typical PC board comprising multiple microprocessors may dissipate approximately 250 W of power. Thus, a rack containing forty (40) PC boards of this type may dissipate approximately 10 KW of power.
The power required to remove the heat dissipated by the components in the racks is generally equal to about 10 percent of the power needed to operate the components. However, the power required to remove the heat dissipated by a plurality of racks in a data center is generally equal to about 50 percent of the power needed to operate the components in the racks. The disparity in the amount of power required to dissipate the various heat loads between racks and data centers stems from, for example, the additional thermodynamic processing needed in the data center to cool the air.
In one respect, racks are typically cooled with fans that operate to move cooling fluid, e.g., air, across the heat dissipating components; whereas, data centers often implement reverse power cycles to cool heated return air. The additional work required to achieve the temperature reduction, in addition to the work associated with moving the cooling fluid in the data center and the condenser, often add up to the 50 percent power requirement. As such, the cooling of data centers presents problems in addition to those faced with the cooling of racks.
Conventional data centers are typically cooled by operation of one or more air conditioning units. The compressors of the air conditioning units typically require a minimum of about thirty (30) percent of the required cooling capacity to sufficiently cool the data centers. The other components, e.g., condensers, air movers (fans), etc., typically require an additional twenty (20) percent of the required cooling capacity. As an example, a high density data center with 100 racks, each rack having a maximum power dissipation of 10 KW, generally requires 1 MW of cooling capacity.
Air conditioning units with a capacity of 1 MW of heat removal generally require a minimum of 30 KW input compressor power in addition to the power needed to drive the air moving devices, e.g., fans, blowers, etc. Conventional data center air conditioning units do not vary their cooling fluid output based on the distributed needs of the data center. Instead, these air conditioning units generally operate at or near a maximum compressor power even when the heat load is reduced inside the data center.
The substantially continuous operation of the air conditioning units is generally designed to operate according to a worst-case scenario. That is, cooling fluid is supplied to the components at around 100 percent of the estimated cooling requirement. In this respect, conventional cooling systems often attempt to cool components that may not need to be cooled. Consequently, conventional cooling systems often incur greater amounts of operating expenses than may be necessary to sufficiently cool the heat generating components contained in the racks of data to the components at around 100 percent of the estimated cooling requirement. In this respect, conventional cooling systems often attempt to cool components that may not need to be cooled. Consequently, conventional cooling systems often incur greater amounts of operating expenses than may be necessary to sufficiently cool the heat generating components contained in the racks of data centers.
Consequently, the inventors have developed systems for collecting temperature data from data centers so that the computing equipment can be cooled based on actual cooling requirements. Such systems can include large numbers of temperature sensors to provide detailed temperature information from many different locations within the data center, allowing a cooling system to provide cooling only where it is needed, and only to the extent actually needed by the electronic systems.
Unfortunately, the traditional approach to sensing large numbers of temperatures distributed throughout a large volume is costly and cumbersome. Typically thermistor or thermocouple sensors are used. These sensors require that a continuous wire be installed from the sensor location to a central instrument where temperature readings are made. Each sensor must be connected to the instrument with its own wire. The wire involved must meet special manufacturing and installation characteristics to provide an accurate result. This results in a very costly and cumbersome installation with large bundles of expensive wire spread throughout the measurement environment. The cost of these methods can be quite high.
A typical temperature data acquisition system could include a central datalogger which contains a switch matrix and analog-to-digital converter, with cold-junction compensation for thermocouple input. Such systems are available that are capable of measuring 60 thermocouple temperature sensors, though this is not a limit. Some systems expand to accommodate a thousand sensors. Unfortunately, this sort of system requires installation of a continuous thermocouple wire from each measurement point to the instrument. Thermocouple wire is a specialized material that must be installed to special requirements for accurate results. Each conductor is a different material, and all junctions must maintain material integrity from sensor to instrument. This requires special connectors and installation procedures.
Industrial versions of this type of equipment are also available, and present similar disadvantages. One such concept is the use of separate “transmitters” at each measurement point that convert from a thermocouple to a network protocol at each measurement point. This is a very costly approach, and requires that power be supplied at each measurement point. Additionally, any installation using traditional techniques would require custom mounting of sensors in the field. This can lead to a visually unappealing installation. Field installation also often results in wire routing that leaves sensor wire vulnerable to damage during operation of the data center.
Accordingly, it has been recognized that it would be advantageous to develop a distributed network of sensors that is simple to install on new or existing equipment rack systems, and that provides a low cost sensor assembly for deploying multiple sensors over a widely distributed area.
The invention advantageously provides a modular sensor assembly for sensing conditions at a computer rack. The sensor assembly includes an elongate flexible body, configured to attach to a computer rack, with a plurality of addressable sensors, disposed along the body and interconnected to a common connector wire. A connector wire lead is provided to interconnect the connector wire to a central system configured to receive and interpret data from the plurality of sensors relating to conditions associated with the computer rack.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention.
Reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the invention as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.
Disposed atop the base layer 22 are multiple flat conductors 24. The conductors can be conductive tapewire, such as copper foil tape with an adhesive backing. Conductive foil or flex circuit tape can be used, such as copper tape foil CK1017 from Cir-Kit Concepts Inc. While two flat conductors are shown in the depicted embodiment, the sensor assembly is not limited to two, for reasons that are discussed below. Of the two flat conductors shown, one conductor 24 a represents a data line and the other conductor 24 b represents a ground line.
A sensor device 14 is attached (e.g. soldered) to the flat conductors 24 via its leads 26. There are a variety of sensor types and sensor products that can be used. One type of temperature sensor that the inventors have employed is a Dallas Semiconductor/Maxim integrated circuits DS18S20-PAR sensor. The sensor assembly can also be used to deploy other digital transducers or sensors with similar connectivity requirements but differing functionalities, such as transducers and sensors for detecting fluid pressure, fluid velocity, humidity, occupancy, light, smoke, door condition, etc. Multiple or redundant conductor assemblies can be developed to address connectivity requirements of a wide variety of transducers and provide customization (or upgrades). The sensor assembly can also be used beyond the rack assembly, for other non-rack related sensors like pressure transducers inside a plenum or temperature sensors for vents.
Each sensor 14 includes at least two connection leads 26. One lead 26 a serves as a data connection lead while the other lead 26 b is a ground connection lead. The data connection lead connects the sensor to a computer controller 110, shown in
Power for the sensor 14 is parasitically drawn from the data line 24 a. Specifically, the sensor includes an internal capacitor, which draws power and charges during data line inactivity. Alternatively, a sensor without an internal capacitor could be used. Such a sensor could include three leads, one of which would be connected to a power supply line (not shown) that would be separate from the data and ground lines. Thus, such a system would require a third conductor line, in addition to the data line 24 a and ground line 24 b shown in the figures.
In the embodiment shown, the sensor 14 is configured to measure ambient temperature a small distance (e.g. 15 mm) from the sensor assembly, and convert the temperature reading into a digital signal. One advantage of implementing this type of sensor is that a central instrument is not needed. Each sensor is capable of independently converting physical temperature data to transmittable digital data. This eliminates the need to carry sensitive analog signals from point to point. The digital data provided by the sensor can be protected by CRC algorithms that prevent distortion of the data.
The connector wire 16 is a multiple conductor wire. In the depicted embodiment, the connector wire includes two conductors 28 a, 28 b, the ends of which are connected (e.g. soldered) to the ends of the flat conductors 24 to provide connectivity to the sensing network. One conductor 28 a is the data line, and the other conductor 28 b is the ground line. It will be apparent that where the sensor assembly includes more than two flat conductors, the connector wire will also include more than two corresponding conductors.
It will be apparent that there must be some way to identify and distinguish the physical location of each sensor in the system. This can be done in several ways. In one configuration, shown in
However, the system is not limited to this configuration. As an alternative, the identification of each sensor 14 can be prescribed with a much smaller address, such as that used by I2C devices. However, this configuration requires at least four conductors on the sensor assembly, and also requires wiring (e.g. printed circuits) with passive components at each sensor for retaining address settings. Alternatively, a user-defined identification code for each sensor (rather than a factory-assigned code) can be prescribed and recorded in the memory device 30, the memory device being factory-set with the user-defined identification codes. As still another alternative, the central computer (110 in
The sensor assembly 10 can include a number of other features for ruggedness, durability, and convenience. In the embodiment shown in
A top layer 38 of plastic or other material is provided over the top of the sensor assembly to cover and protect it. This top layer can be of the same material and same basic size as the base layer 22 described above. An adhesive or adhesive layer, such as thin double-sided adhesive tape (not shown), can be applied to the top of the flat conductors 24 to adhere the top layer to the base layer and flat conductors between the sections of cushioning material 36.
The sensor assembly 10 can be disposed within a molding or other elongate protective structure, such as a channel 40 as depicted in
Other configurations and materials can also be used for the sensor assembly. For example, as shown in
The computer rack 60 houses a plurality of components 70, e.g., processors, micro-controllers, high speed video cards, memories, semi-conductor devices, and the like. The components may be elements of a plurality of subsystems (not shown), e.g., computers, servers, etc. In the performance of their electronic functions, the components, and therefore the subsystems, generally dissipate relatively large amounts of heat. Because computer rack systems have been generally known to include upwards of forty (40) or more subsystems, they may need substantially large amounts of cooling resources to maintain the subsystems and the components generally within a predetermined operating temperature range. Additionally, the temperature of cooling air supplied by a data center cooling system is likely to vary based on distance between the cooling equipment and the computer rack. Accordingly, temperature readings associated with the operation of the computer rack are gathered at multiple points in the vertical and horizontal directions.
The sensor assemblies 10 can be configured to fit onto installation features built into the rack 60. For example, the front sensor assembly 10 a, shown in
As shown in
It is also notable that the rear sensor assembly 10 b includes an overhead sensor 14 a that is disposed on a portion of the sensor assembly extending above the rack 60. This configuration can be accommodated in various ways. For example, where the sensor assembly is disposed inside the rear doors 66, the overhead portion of the sensor assembly can be a discontinuous portion that is connected to the remainder of the assembly via a connector wire. This wire can extend unobtrusively between the adjacent door and the body of the rack. The overhead portion of the sensor assembly can be attached to additional support structure, such as an upright rod, that is associated with the rack. Alternatively, the overhead portion of the sensor assembly can include a support member like the support member 58 shown in
The sensor assemblies 10 are designed to facilitate easy mounting on an equipment rack, either at the factory before shipment to the customer, or at the customer site for installation as an option. This is accomplished by building mounting features into the rack that will accommodate the sensor assembly. These features can be in the form of a channel or series of holes in the surface of the rack (designed to receive snap rivets or other connectors), and are designed to fit mounting provisions on the rack. When a sensor assembly is not installed at a given location that is configured to receive one, a compatible blank trimming strip can be installed at that location to cover the exposed mounting locations. In this way a cosmetically appealing appearance can be maintained whether or not the sensor assembly is installed.
Mounting point features designed into equipment racks make installation of the sensor assembly a simple process. The sensor assemblies may also be retrofitted onto racks without mounting features by using adhesive to connect the sensor body 12 to the rack, such as by using double-sided adhesive tape.
The sensor assembly solves some of the manufacturing and installation problems for networked environmental sensors. It provides a system for deploying a widely distributed sensor network with simple parallel wiring. The labor-intensive and costly installation process of traditional temperature measurement is replaced by an unobtrusive, easily installed assembly. Separate specialized electrical connections are replaced by a single parallel circuit of standard telecommunications-grade wiring. Advantageously, the sensor assembly provides broad sensor coverage in an easily installed package. The sensor assembly can be produced at a low cost, and is easily manufactured using existing assembly techniques.
A cost effective network of digital sensors has many advantages over traditional methods. Systems sometimes referred to as “smart cooling” systems have been developed to provide a networked environmental monitor comprising a plurality of temperature sensors, located at various locations throughout a data center, to dynamically collect temperature data at various locations within the data center. By dynamically collecting temperature data at various locations within the data center, the cooling resources of the data center can be allocated based on the actual cooling requirements of the data center. As a result, substantial savings in operational costs related to the operation of the data center cooling resources is possible.
The sensor assembly shown herein is compatible with “smart cooling” systems and their associated temperature data collection system. The various elements and aspects of a networked environmental monitoring system for collecting and using temperature data from a large number of sensors in a data center are depicted in
The method of collecting temperature data using the system depicted in
The computer system 110 may be any of a variety of different types, such as a notebook computer, a desktop computer, an industrial personal computer, an embedded computer, etc. The computer system includes a processor and various other components such as a user interface (e.g. keyboard, mouse, voice recognition system, etc.), and an output device (e.g. a computer monitor, a television screen, a printer, etc.), depending upon the desired functions of the computer system. A communications port can also be coupled to the processor to enable the computer system to communicate with an external device or system, such as a printer, another computer, or a network.
The computer system 110 may also be utilized in conjunction with a distributed computing environment where tasks are performed by remote processing devices that are linked through a communications network. Examples of such distributed computing environments include local area networks of an office, enterprise-wide computer networks, and the Internet. Additionally, the networks could communicate via wireless means or any of a variety of communication means.
Referring back to
Each sensor assembly 10 includes a connector wire 16 with a mechanical connector 18 at its end. Associated with each rack 60 is a connector board 80, like the connector board 140 shown in
The input ports 82 can be RJ-11 phone line type ports or any of a variety of types of ports. As an operative example, the first port 82 a can be configured to connect the connector board 80 to the temperature collection module 110 or directly to the central computer system 120, while the second data port 82 b can be configured to connect to the sensor assembly 10, to collect temperature data from the plurality of sensors 14. Additionally, the first data port 82 a can be configured to connect the connector board to another connector board associated with another rack, thereby enabling multiple connector boards to be connected to a central computer system in a daisy chain fashion, like that shown in
A third input port 82 c can also be provided to connect to a second sensor assembly (not shown) that can be associated with the rack. This sort of configuration is suggested by
In the connection scheme shown in
Referring back to
The temperature collection logic periodically queries the data table which contains the temperature readings of each plurality of the sensors. In order to access individual sensors it is necessary to know the address identifier of each of the individual sensors along with the physical location. This issue is complicated by the fact that the individual sensors are factory programmed with unique address information that is not re-programmable. However, this problem is solved by the memory device associated with each sensor assembly. The memory device stores the identifier of each sensor on the sensor assembly. The memory devices are programmed during the assembly of the sensor assembly. Data is stored in the memory device that indicates a unique identifying number for the sensor assembly itself. Also stored in the memory are the unique 1-wire addresses of each sensor device installed on the sensor assembly. These addresses are stored in a table in the same order as the physical order of the devices on the sensor assembly. It would also be possible to associate the sensor assembly with a particular rack if it was installed on this rack at the factory. Alternatively the rack information could be programmed in the field using a simple tool designed for this purpose. Using this information, it is possible for a temperature collection module to automatically configure its data collection logic when a sensor assembly is added to its 1-wire network.
Additionally, in another alternative embodiment, the temperature collection module can be implemented as a “row manager” device. Accordingly, the module can be capable of communication with an Ethernet network connection while communicating with the plurality of sensors.
In accordance with one method of collecting temperature data, a temperature data acquisition process can begin with the periodic querying of each of the sensors in the data center, providing a “start conversion” command whereby the process of taking temperature readings from the individual sensors is initiated. This process takes approximately ¾ to one second per sensor when using the parasitically powered sensor devices described above. If faster results are desired, sensors are available with a separate power supply pin for a much faster response. This would be one configuration in which three conductors in the sensor assembly and in the connecting wire would be needed.
Once the temperature is measured from each sensor, temperature collection logic stores the temperature readings in a data table and generates a temperature profile of the data center based on the temperature readings. Separate temperature tables can be generated based on the varying locations of sensors. For example, based on the location of the sensors temperature profiles can be generated for the front of the rack, the back of the rack, etc.
In varying embodiments, the data center could employ more than one temperature collection module. In this case, the data table in each module will only contain part of the temperature profile of the data center. Accordingly, the central computer can assemble partial profiles of the data center. These partial profiles can subsequently be combined to form a global temperature profile of the data center.
The method of obtaining temperature data from an installation of sensors is generally as follows. A first step includes periodically querying of each of the sensors in the data center. A second step includes providing an initiation command. A third step includes reading the measured temperature of each of the sensors. A final step involves generating a temperature profile of the data center based on the temperature readings. The temperature profile can include a variety of profiles based on the locations of the sensors, and can be presented in a 3-dimensional matrix view format. The above-described method may be implemented, for example, by operating a computer system to execute a sequence of machine-readable instructions. The instructions may reside in various types of computer readable media.
Although the application and use of the sensor assembly is disclosed in the context of a data center, one of ordinary skill in the art will readily recognize that the functionality of the varying embodiments of the sensor assembly can be utilized in a variety of different facilities. Specifically, this type of sensor assembly is by no means limited to data center applications, and is not limited to temperature sensing.
It is to be understood that the above-referenced arrangements are illustrative of the application of the principles of the present invention. It will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth in the claims.